[evlatests] Gross X-band RFI

[Rick Perley]

     The RFI situation in X-band, between 10 and 12 GHz, seems to have 
gotten very much worse recently.

     Attached is a 'waterfall'-type plot of the RFI on a single 
baseline.  The vertical axis is time, the horizontal axis is linear in 
frequency, from 10 GHz through 12 GHz.  The individual spectral windows 
are identified on the bottom, from 1 through 16. This is a fairly short 
baseline, from N06 to W02.  The polarization is 'RL'.  All four 
polarizations looks exactly the same.  The dark grey areas are at a 
level of about 2 Jy, the brightnest white is 186 Jy (in polarized flux!!!).

     The source is 3C273, which at a declination of +02, is near the 
geostationary satellite belt.  The abundant broad-band RFI so evident in 
the displayed plot is also seen on the nearby calibrator (declination 
+03), but not on the distant calibrators 3C286 (Declination +30), or 
OQ208 (declination +28).  So it is quite clear that the source is in the 
'Clarke' belt.

     What is concerning to me is the fraction of the data obliterated by 
RFI -- towards the end of the run (HA ~+2) -- top plot -- about half the 
2 GHz bandwidth is rendered useless.

     I'll be working on the Ku data next -- stay tuned for more 
revelations...

     Rick


-------------- next part --------------
A non-text attachment was scrubbed...
Name: GrossRFI.png
Type: image/png
Size: 84349 bytes
Desc: not available
URL: <http://listmgr.nrao.edu/pipermail/evlatests/attachments/20191017/edfc8e3a/attachment-0001.png>